Diketahui jari jari 21 cm dan sudut AOB=90 Tentukanlah a. Keliling lingkaran b luas lingkaran c. Panjang busur AB d.luas juring AOB moho cra kerjanya a smpai d

[tex]a.2\pi \: r \\ 2 \times 22 \div 7 \times 21 \\ 2 \times 66 \\ 132 \\ b.\pi \: r {}^{2} \\ 22 \div 7 \times 21 {}^{2} \\ 22 \times 63 \\ 1386 \\ c.90 \div 360 \times 2\pi \: r \\ 1 \div 4 \times 2 \times 22 \div 7 \times 21 \\ 1 \div 4 \times 132 \\ 33 \\ d.90 \div 360 \times \pi \: r {}^{2} \\ 1 \div 4 \times 22 \div 7 \times 21 {}^{2} \\ 1 \div 4 \times 1386 \\ 346.5[/tex]
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